Here are a few things you can try.
Get yourself an external disk drive - ranga suggested this. It is really worth it. Now to retrieve your data-
1. Wash the CD with a mild liquid soap like DETTOL HANDWASH, DRY THE CD COMPLETELY and try reading it again - this actually works sometimes. I've tried it.
2. If that does not work, here are some software worth trying.
UNSTOPPABLE COPIER - very time consuming but worth it. You do want your data don't you?
ISO BUSTER - have not tried this.
They skip the affected areas.
You can at least retrieve parts of your file.
INFO COURTESY PC WORLD SEP 2007